Digital logic: gates, K-maps & flip-flops worksheet with answers

Free printable Digital logic: gates, K-maps & flip-flops worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy

For the logic circuit shown, how many of the 8 combinations of the inputs A, B and C give the output F = 1? Find N.

A, B, C → F

N =

2.Easy

The propagation delay of every gate is written under it. Find the worst-case propagation delay t_pd from the inputs to the output F.

N1: 1 nsG1: 2 nsG2: 4 ns

t_pd = ns

3.Medium

Use the Karnaugh map to find the minimal sum-of-products (SOP) form of F(A, B, C, D) = Σm(0, 2, 4, 5, 6, 7, 8, 9, 10, 11, 14, 15). How many product terms N does it have?

F(A, B, C, D) = Σm(0, 2, 4, 5, 6, 7, 8, 9, 10, 11, 14, 15)

N =

4.Medium

A 4-to-1 multiplexer has its select inputs S₁ = A and S₀ = B, and its data inputs tied to I₀ = C′, I₁ = 1, I₂ = 1, I₃ = C. For how many of the 8 combinations of A, B and C is the output F = 1? Find N.

I₀ = C′I₁ = 1I₂ = 1I₃ = C

N =

5.Hard

Find the minimal SOP form of F(A, B, C, D) = Σm(1, 3, 9, 13, 14) + d(0, 2, 5, 7), where d marks the don't-care conditions. How many literals L does it contain?

F(A, B, C, D) = Σm(1, 3, 9, 13, 14) + d(0, 2, 5, 7)

L =

6.Hard

A synchronous mod-6 counter counts 0, 1, …, 5 and then returns to 0. It starts at 0. Which count Q (in decimal) does it show after 15 clock pulses?

Q₀ = 015N = 6

Q =

Answer key

1. N = 1
2. t_pd = 7 ns
3. N = 4
4. N = 6
5. L = 8
6. Q = 3

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